Fuel supply apparatus
AssigneeDenso Corporation
InventorsTakeru Nagao, Ken Uchiyama
Life of this patent
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Abstract
In the start mode of a fuel supply apparatus, a subtraction value of an electric power is obtained in view of an SCV characteristic. Furthermore, a common correction value is employed as the subtraction value in order to increase an actual fuel discharge amount when the internal combustion engine is started, whereby a fuel pressure in an accumulator agrees with the target value even if an individual pump unit shows a lowest limit in the variations of the discharge amount. The common correction value is shared among the individual pump units. Even if a starting characteristic is not acquired for each of the individual supply pumps, the internal combustion engine can reliably be started.
Claims4
A fuel supply apparatus supplying a fuel to an internal combustion engine through an accumulator in which the fuel is accumulated at a high pressure, comprising:
- a pump unit having a high-pressure pump and an amount adjusting portion;
- and
- a control unit controlling the pump unit;
- and
- a relief valve releasing the fuel from the accumulator in accordance with an opening degree of the relief valve, wherein
- the high-pressure pump suctions the fuel, pressurizes the fuel and discharges the fuel to the accumulator,
- the amount adjusting portion adjusts an amount of the fuel which is suctioned by the high-pressure pump and adjusts the amount of the fuel which is discharged by the high-pressure pump in accordance with an amount of an electric power supplied to the amount adjusting portion,
- the control unit stores an control characteristic of the amount adjusting portion, which shows a correlation between the amount of electric power and a discharge amount of the high-pressure pump,
- the control unit calculates a requesting discharge amount for bringing the fuel pressure in the accumulator to substantially agree with a target pressure,
- the control unit calculates a target electric power based on the requesting discharge amount in view of the control characteristics,
- the control unit corrects the target electric power in such a manner as to increase an actual discharge amount of the high-pressure pump,
- the control unit defines a start mode in which the target electric power obtained by applying the requesting discharge amount to the control characteristics is calculated as a final target electric power so that the actual discharge amount is increased,
- the final target electric power is computed by using of a common correction value so that the fuel pressure in the accumulator substantially agrees with the target fuel pressure even if the pump unit individually shows a largest variation of the discharge amount, wherein the common correction value is shared among individual supply pump, and
- in the start mode, the relief valve and the amount adjusting portion are controlled in such a manner that the fuel pressure in the accumulator substantially agrees with the target fuel pressure.
Dependencies are inferred from the claim text.